The Centers for Disease Control and Prevention's (CDC) Advisory Committee on Immunization Practices (ACIP) is conducting a comprehensive review of the established childhood vaccine schedule, which currently outlines over 30 vaccine doses against more than a dozen diseases. This review, initiated by a committee whose members were appointed by Health and Human Services (HHS) Secretary Robert F. Kennedy Jr., coincides with an updated CDC website statement on vaccines and autism, as well as broader policy changes regarding vaccine recommendations and funding. The process is generating varied responses from public health organizations, medical professionals, and government officials, particularly in light of increasing outbreaks of vaccine-preventable diseases.
CDC Committee Initiates Childhood Vaccine Schedule Review
The Advisory Committee on Immunization Practices (ACIP), established in 1964 to inform medical practice and insurance coverage for vaccinations, is reviewing the long-standing childhood vaccine schedule.
This scrutiny occurs amidst a rise in outbreaks of diseases such as measles and pertussis, which public health officials attribute to declining immunization rates.
Earlier this year, Health and Human Services Secretary Robert F. Kennedy Jr. replaced all incumbent ACIP members. The committee's current chair is Dr. Kirk Milhoan, a pediatric cardiologist who is also a fellow with the Independent Medical Alliance, a group that has recommended ivermectin for COVID-19 treatment. A September meeting of the committee encountered procedural difficulties, resulting in a tabled vote on the hepatitis B vaccine recommendation and a change in chairmanship. A new working group within ACIP has been tasked with scrutinizing the entire childhood vaccine schedule.
CDC Alters Stance on Vaccine-Autism Link
CDC Updates Website Statement
The CDC has updated its official position regarding a potential connection between vaccines and autism on its website. The site now states that a link between vaccines and autism "cannot be ruled out," a shift from its prior long-held assertion that no such link exists. This update was made despite a substantial body of research consistently indicating no connection between vaccines and autism.
HHS spokesperson Andrew Nixon stated that the claim "vaccines do not cause autism" is not considered evidence-based, citing that studies have not definitively excluded the possibility of infant vaccines causing autism. Nixon added that the department has initiated a comprehensive assessment into the causes of autism.
Expert Reactions and Concerns
Public health organizations have issued statements in response. The American Academy of Pediatrics reported that over 40 studies across seven countries, involving more than 5.6 million individuals since 1998, have concluded there is no link between vaccines and autism. The Autism Science Foundation commented that the new statement demonstrates a "lack of understanding of the term 'evidence'." Dr. Paul Offit of the Children's Hospital of Philadelphia characterized the website changes as consistent with "anti-vaccine rhetoric."
Dr. Demetre Daskalakis, a former top CDC official, stated that career scientists at the CDC were not involved in developing the updated information and that the data presented were unvetted. Two anonymous current CDC staffers expressed concerns about the credibility of the agency's vaccine information, describing it as "anti-science."
The CDC's main webpage concerning autism and vaccines still displays a header stating "Vaccines do not cause autism*." A footnote on this page clarifies that this header has not been removed due to an agreement with Senator Bill Cassidy, chair of the U.S. Senate Health, Education, Labor and Pensions (HELP) Committee. However, new statements added to the page include, "The claim 'vaccines do not cause autism' is not an evidence-based claim because studies have not ruled out the possibility that infant vaccines cause autism," and "the public has 'largely ignored studies showing that vaccines do cause autism.'" The latter assertion conflicts with established scientific consensus, which includes the retraction of a 1998 study linking the MMR vaccine to autism due to being fraudulent.
Secretary Kennedy's Policy Shifts and Directives
Divergence from Confirmation Pledges
Health and Human Services Secretary Robert F. Kennedy Jr.'s actions have diverged from several pledges made during his confirmation hearings. In January 2025 hearings, Kennedy assured senators, including Senator Elizabeth Warren, of his support for childhood vaccines and the existing vaccination schedule. Senator Bill Cassidy also publicly stated Kennedy's commitment to maintain ACIP recommendations without changes.
Key Policy Changes Implemented
Since his confirmation, Secretary Kennedy's administration has implemented several policy changes:
- ACIP Membership: All incumbent ACIP members were replaced with new appointees, some of whom reportedly oppose certain vaccines.
- Vaccine Recommendations: The CDC removed its universal recommendations for seven immunizations, including respiratory syncytial virus, meningococcal disease, flu, COVID-19, hepatitis A, hepatitis B, and rotavirus. These are now recommended for high-risk children or after doctor-parent consultation.
- Vaccine Funding: Despite a pledge not to undermine vaccine funding, the CDC withdrew $11 billion in COVID-era grants supporting local health department vaccination programs, though a federal judge later ordered HHS to distribute these funds. The National Institutes of Health (NIH), part of HHS, withdrew research grants for studies on vaccine hesitancy. Additionally, Kennedy ordered the cancellation of $500 million worth of mRNA vaccine research in August.
- Thimerosal: The new ACIP subsequently called for the removal of thimerosal, a preservative used in some flu vaccines, despite previous debunking of safety concerns.
HHS spokesperson Andrew Nixon stated that Secretary Kennedy "continues to follow through on his commitments" to Senator Cassidy, including accepting recommendations for key agency roles and retaining specific language on the CDC website. Senator Cassidy's office has not publicly addressed questions regarding whether Kennedy's actions have broken these commitments. Secretary Kennedy has also indicated his view that American children receive a higher number of vaccines.
Review of Specific Vaccinations Under Scrutiny
The ACIP working group is reviewing several specific vaccination protocols:
Hepatitis B Vaccine
The committee is expected to vote on a potential change to the recommendation for universal hepatitis B vaccination for all newborns within 24 hours of birth. Possibilities include delaying the shot or requiring a detailed parental discussion. The CDC recently dropped its universal recommendation for newborn hepatitis B vaccination. Arguments for a change suggest increased screening of pregnant women and vaccinating only infants of positive mothers could be sufficient, noting some other countries do not administer the dose universally at birth.
Conversely, opponents argue the virus can spread through various means, and over 90% of infected infants develop chronic infections, increasing risks for liver disease and cancer. An analysis presented at past ACIP meetings indicated that delaying vaccination by a few months could result in over $222 million in additional healthcare costs and hundreds of preventable deaths annually.
MMR (Measles, Mumps, Rubella) Vaccine
The committee is investigating the option of separating the combined MMR vaccine into three individual shots. Proponents of the combined vaccine argue that separate shots would necessitate more doctor visits and injections, potentially leading to more missed vaccinations, and note that developing new individual shots would take years.
Aluminum Adjuvants
The committee is examining the safety of aluminum-containing adjuvants, which are used in several important vaccines to enhance immune response and have been utilized for nearly a century. A working group is evaluating whether specific aluminum adjuvants increase the risk of asthma. Most public health experts indicate a lack of evidence supporting safety concerns, and a recent large Danish study found no associated danger. Critics of aluminum adjuvants assert potential links to health issues such as autism and attention deficit hyperactivity disorder, claims which Dr. Frank Virant of the American Academy of Allergy, Asthma & Immunology states have no evidence. Removing aluminum from vaccines would compromise their effectiveness, and no immediate substitute vaccines are currently available.
U.S. Vaccine Schedule Compared to Other Nations
Directive for Alignment
President Trump issued a memorandum directing Secretary Kennedy and the acting CDC director to align U.S. childhood vaccine recommendations with practices from peer nations, specifically mentioning Denmark.
Denmark's routine childhood immunization schedule recommends vaccination against 10 diseases, compared to the U.S. schedule, which has historically recommended routine universal vaccination against 16 diseases.
Challenges in Direct Comparison
Experts argue that directly adopting another country's vaccine schedule in the U.S. is not feasible due to significant differences:
- Demographics and Health Systems: Denmark has a population of approximately 6 million, less racial and ethnic diversity, and a unified health system with a national health registry that tracks individuals from birth to death. The U.S. has over 343 million people, greater racial and ethnic diversity, wider income disparities, a fragmented insurance system, a significant uninsured population, no national health registry, and significant gaps in continuity of care.
- Parental Leave and Healthcare Access: Danish families typically receive about a year of paid parental leave, potentially reducing infants' exposure to diseases, and the country provides free, universal health care. In the U.S., these factors are cited by experts as reasons for broader vaccine recommendations due to challenges in reliably identifying and following up with every at-risk individual.
- Risk Factors: The U.S. also has higher rates of childhood obesity and asthma than Denmark, which can increase vulnerability to certain diseases.
Josh Michaud of KFF stated that the U.S. schedule aligns closely with 30 countries in the European Center for Disease Prevention and Control, suggesting Denmark appears to be an outlier.
Countries like Germany, France, and Italy recommend 15 or more vaccines. Dr. Jake Scott of Stanford University characterized Denmark's approach as "unusually minimalist" even compared to other Nordic nations such as Sweden, Norway, and Finland, which cover more diseases. Dr. William Moss, an epidemiology professor at Johns Hopkins Bloomberg School of Public Health, clarified that variations in vaccine schedules among countries are not typically based on concerns about vaccine safety or efficacy.
Public Health Context and Expert Perspectives
Historical Efficacy and Current Schedule Benefits
For decades, children have received a series of vaccinations beginning at birth. Routine childhood vaccinations have significantly reduced the prevalence of many infectious diseases. Dr. Stanley Plotkin, a veteran vaccine scientist, noted that contemporary parents are less likely to worry about a child dying from an infectious disease compared to past generations.
Proponents of the current vaccine schedule emphasize that each vaccine undergoes rigorous evaluation for safety and effectiveness before inclusion and continuous monitoring post-implementation. They assert that the timing of vaccine administration considers a child's immune system optimal response and periods of highest disease risk. Dr. Yvonne Maldonado, a pediatric infectious disease expert at Stanford University, described the current vaccine schedule as "incredibly safe and incredibly effective." Children typically receive these vaccinations at a young age to protect them during periods of high vulnerability.
Immune System Capacity and Risks of Delay
Concerns have been raised regarding the potential for the number of antigens and ingredients in vaccines to overwhelm a child's immune system. However, scientists like Dr. Maldonado maintain that babies' immune systems are capable of handling the exposure, noting children encounter more natural microbial stimulation than from vaccines. Vaccines have also been refined over decades to minimize ingredient counts. Dr. Paul Offit stated that the approximately 170 different components in the current schedule's various shots are "less than the vaccines that Robert F. Kennedy Jr. and I got as children of the early 1950s."
Dr. Sean O'Leary, chair of the American Academy of Pediatrics's committee on infectious diseases, stated that delaying or spacing out vaccines introduces unnecessary risk. Dr. Raynard Washington, director of the Mecklenburg County Public Health Department, expressed concern about any potential barriers to vaccination given rising case numbers.
Policy Implementation and Legal Questions
The Department of Health and Human Services (HHS) postponed a planned announcement concerning "children's health" and the childhood vaccination schedule, rescheduling it for after the new year. Media reports had suggested this announcement might have involved an overhaul of the childhood vaccination schedule.
Legal experts, including Dorit Reiss, a law professor at the University of California, San Francisco specializing in vaccine legal and policy issues, have raised questions regarding the authority of the health secretary to implement significant vaccine policy changes without following established processes. Reiss indicated that bypassing the CDC's Advisory Committee on Immunization Practices for such major changes could make the administration vulnerable to legal challenges.